The City Development Initiative for Asia, the Asian Development Bank, other multilateral agencies, and national governments are funding sewerage systems for medium and large cities throughout Asia. Even at “full” sewerage coverage, cities often find that some, if not many, buildings are still reliant on septic tanks, pits, or other onsite systems. For cities with or that are planning sewerage systems, co-treatment may enable citywide sanitation by minimizing the need for standalone fecal sludge treatment plants.